Circuit board socket

ABSTRACT

A circuit board disconnect socket having an elongate hollow body open at one end, a strap surrounding the open end and a pair of contact arms extending from the strap and into the body. A reinforcing spring is wrapped around the strap and includes spring arms extending along the outside of the contact arms. Insertion of a lead between the contact arms spreads the arms apart and stresses the spring.

PMENTEU [15u25 |915 SHEET 10F 4 INVENTOR.

PMENIEU mm |915 SHEET 3 UF 4 INVENTOR. LloLjol Mancini Thomasv Hooke?,

PATENTEUUECES |915 A 3.781. 770 SHEET u of 4 INVENTOR. L.|Ol.)d Mancini BY Thomas Hooker, His Aftovnelj CIRCUIT BOARD SOCKET The invention relates to an improved disconnect socket having a socket body with a pair of contact arms and a spring wrapped around the socket body including spring arms lying on top of contact arms in the body. The pring arms provide contact pressure for forming a high pressure electrical connection between the contact arms and a male lead inserted into the socket. In a socket of this type, the spring is elastically stressed during deflection for mating with both thick and thin leads. Because the spring is stressed elastically the high contact pressure is retained after repeated insertions of leads into the socket and even when a thin lead is inserted into the socket subsequent to insertion and withdrawal of a thick lead.

The bi-metal construction results in a compact socket having a high contact force. This in part results from the fact that when a lead is inserted the entirity of the spring is stressed to bias the contact arms against the lead. The spring arms are stressed as cantilever springs and the portions of the spring wrapped around the strap are stressed as both torsion springs and additional cantilever springs. Thus, the spring pressure exerted against the contact arms results from stressing of all of the various spring components. This arrangement is highly efficient since all of the spring is used to provide the contact pressure. Because all of the spring is stressed during insertion of the lead, the socket is much smaller than one using conventional cantilever springs alone to provide an equivalent pressure on the contact arms. Because the spring is not part of the electrical circuit high yield strength material may be used resulting in greater contact pressure. The reduction in size of the disconnect socket with the improved spring properties permits use ofthe socket in circuits where a minimum of space is available for sockets or where a number of sockets must be mounted on a circuit board or like member in dense configuration.

One form of spring used to bias the contact arms into engagement with the lead inserted into the socket is formed from a continuous length of spring wire and includes two pairs of cantilever spring members, torsion springs extending to one side of the ends of the cantilever spring members and bridging cantilever springs joining the ends of the torsion springs. One of the pairs of cantilever spring members is formed from a U- shaped portion of spring wire while the other cantilever spring members comprise the free ends of the wire. The ends of the cantilever spring members engage the free ends of the contact arms to bias the same toward the interior of the socket. The arms are reinforced to p revent buckling and include contact points located approximately halfway along the length of the arms for engaging the lead. Since the contact arms are rigid and the spring engages the ends of the contact arms, the contact pressure on the lead is greater than the contact pressure between the ends of the cantilever spring members and the contact arms, thus providing an improved connection between the lead and the socket.

ln another embodiment of the invention the spring is formed from a hollow hourglass-shaped portion of flat metal spring stock. This spring also includes the two pairs of cantilever spring arms, the torsion springs and the bridging cantilever springs. The strength of the individual spring members of either spring may be adjusted to assure that the desired spring contact pressure is achieved.

The socket may be mounted on a circuit board by means of a contact pin secured to a collar at the end of the socket body away from the lead receiving opening. Alternatively, a solder resistant plug may be crimped within the collar so that solder does not wick into the socket interior when the socket is mounted in a circuit board hole and the board is wave soldered.

For low profile mounting, tabs may be struck from the body side walls between the contact fingers for forming a solder connection with printed circuitry on the top of the board. ln this case the end of the terminal opposite the lead receiving end may be positioned within an oversize circuit board hole.

An alternative low profile mounting may be achieved by positioning the socket end away from the lead receiving end within a solder resistant cup which in turn is mounted in an oversize circuit board hole and resoldered to the board.

Circuit board sockets of the type disclosed may be used to receive leads attached to circuit elements such as relatively delicate integrated circuit modules. The socket spring may be pivoted relative to the socket body to permit movement of the cantilever spring members to either side of the socket axis thereby permitting insertion of misaligned leads into the socket without subjecting these leads to un-balanced forces. ln this way integrated socket leads which are somewhat off-center may be inserted into the socket without subjecting the module itself to forces likely to injure or break it.

The following patents disclose disconnect sockets of the type having a pair of opposed cantilever contact arms: Deakin U.S. Pat. No. 3,120,418, Evans U.S. Pat. No. Re. 26,837 and Gluntz U.S. Pat. No. 3,363,224. ln each of the sockets disclosed in these patents contact pressure is provided by the resiliency of the spring arm itself so that the socket is not capable of mating with leads of different thicknesses while retaining the high contact pressure. The arms also form part of the electrical circuit through the socket. For a given size socket the integral contact and spring arms are unable to provide contact pressures as high as those achieved in a socket of the type disclosed. Further, insertion of leads into a conventional socket having integral contact and spring arms stresses the arms beyond their yield point thus resulting in reduced contact pressure. The disclosed socket avoids this problem because deflection of the contact arms stresses the spring without exceeding the elastic limits of any of the spring components which contribute to the total contact force. Thus the socket may be reliably used in situations where leads are plugged and unplugged a number of times without decrease in the contact pressure. The integrity of the electrical connections between the socket and the lead is maintained despite repeated insertions of the lead and stressing of the spring. The socket body is formed of highly conductive metal and need not have a high yield strength while the spring material has a high yield strength and need not have high electrical conductivity.

Other objects and features of the invention will become apparent as the description proceeds, especially when taken in conjunction with the accompanying drawings illustrating the invention, of which there are four sheets.

IN THE DRAWINGS:

FIG. 1 is a perspective view of a circuit board with components attached thereto by sockets according to the invention;

FIG. 2 is a partially broken away perspective view illustrating one of the sockets of FIG. 1;

FIGS. 3 and 4 are sectional views taken along lines 3 3 and 4 4 respectively of FIG. 2;

FIGS. 5, 6, 7 and 8 are sectional views taken through the socket of FIG. 4 along lines 5 5, 6 6, 7 7 and 8 8 respectively;

FIGS. 9, 10 and 11 illustrate further embodiments of the invention;

FIG. 12 is a sectional view taken along line 12-12 of FIG. 10;

FIG. 13 is a sectional view taken along line 13 13 of FIG. 11;

FIGS. 14, 15 and 16 illustrate still further embodiments of the invention;

FIG. 17 is a sectional view taken along line 17 17 of FIG. l5;

FIG. I8 is a sectional view taken along line 18-18 of FIG. 14;

FIG. I9 is a representational view illustrating pivoting of the spring in a socket in response to the position ofthe lead within the socket;

FIG. 20 illustrates engagement between one end of the spring fingers and the socket contact arm;

FIG. 21 and 22 illustrate the socket body after formation and prior to mounting of the-spring;

FIG. 23 is a sectional view taken along line 23-23 of FIG. 21;

FIG. 24 is a perspective view of a further embodiment of the invention provided with a stamp-formed spring;

FIGS. 25 and 26 are respective views of the springs used in the embodiment illustrated in FIGS. 2 and 24 respectively; and

FIGS. 27 and 28 illustrate the formation of the spring of FIG. 26.

DETAILED DESCRIPTION OF THE INVENTION As illustrated in FIG. l, rows of spaced apart disconnect sockets 10 may be mounted on a circuit board for forming electrical connections with the leads 12 extending from a circuit element 14 and into the sockets. The circuit element may be an integrated circuit.

Each socket l0 includes a stamp-formed socket body 16 with a reinforcing spring 18 wrapped around the strap 20 at the end of the body adjacent lead receiving opening 17. A pair of like contact arms 22 formed from the sides of the socket body extend into the interior of the socket from opposed portions of strap 20. The spring 18 includes opposed spring fingers 24 and 26 which extend from the outside of the strap portion along the outside surfaces of the contact arms and engage the contact arms adjacent their free ends. The spring fingers are joined by spring portions 28.

As illustrated in FIG. 2, socket 10 may be provided with a collar 30 at the end of the body 16 away from lead receiving opening 17 to facilitate mounting ofthe socket within a hole 32 formed through the thickness of circuit board 34. The collar may be secured to a pin 35 by a crimp and ref'low solder connection. The pin may be used for making connections between socket I0 and other circuit elements by either a wire wrap or socket connector mounted on the pin.

The construction of socket 10 will now'be described in further detail. As indicated in FIG.5, the socket body 16 is generally square in cross section and includes a pair of opposed flat sides 36 joining sides 38 from which the contact arms 22 are formed. Ths strap 20 is formed from the ends of the socket side walls ad- 5 jacent opening 17 and is flared outwardly to define a funnel-shaped lead-in for guiding a lead 12 between arms 22. A seam defined by the edges of the blank from which the socket body is formed extends along one side 36. Rectangular collar 30 is reduced in cross section somewhat from that of body 12 so that the connecting portion 42 joining the body and collar forms a seat for a limiting insertionof the socket into circuit board hole 32.

The width of` contact arms 22 decreases from the strap 20 to the free ends 44 thereof. The lower half 46 of the contact arms are bent away through a shallow angle from the upper half of the arms to define lead contacts 48 located in the medial portions of the arms. The free ends 44 are bent outwardly around a small radius to provide recesses for retaining the free ends of the spring arms 24 and 26. 4

Insertion of lead 12 into the socket body bends the contact arms 48 outwardly of the body. Since the arms are stamped from the body it is desirable to provide clearance between the arms and the edges ofthe finger cut-outs in sides 38. Binding between the free ends 44 and the lower edges 50 may be eliminated by bending the free ends outwardly to thereby foreshorten the arms. The bend at the medial portion of the arms also serves to foreshorten the arms. Because the arms are tapered the foreshortening moves the lower half of the arms away from the edges 50 to permit flexing of the arm into the cut-out without binding.

Bin-ding between the upper portions of contact arm 18 and the cut-outs may be eliminated by bending the upper edges 52 of the cut-outs 50 outwardly of the socket as indicated-in FIG. 2. FIGS. 5, 6 and 7 illustrate that the upper edges 52 are gradually bent outwardly from the middle of the cut-out to the end of the cut-out adjacent the strap 20. Thus, in FIG. 5, the portions 54 of side walls 38 are bent slightly outwardly of the socket; in FIG. 6 the portions are bent out at an angle of approximately 45; and in FIG. 7 the portions are bent out through 'an angle of nearly 90 so that they form extensions of the adjacent side walls 36. Bending out of the wall portions 54 increases the width ofthe cut-out to permit bending of the contact arms within the cut-outs without engagement or binding between the arms and the edges of the cut-outs.

It is important that the contact arms are rigid along their length in order to assure that they do not buckle during insertion of the lead with a resulting reduction of the pressure at contacts 48. The arms may be inwardly dished as indicated in FIGS. 4 and 5 to provide additional beam strength. With this construction it is possible to locate the contact points 48 at a position nearer the strap 20 than the engagement between the contact arms and the spring fingers. The construction results in a contact force between each arm 22 and the lead 12 greater than the force between the spring finger and the end of the contact arm.

FIG. 25 illustrates reinforcing spring 18 prior to mounting on socket body 16. The spring is formed from a single length of spring wire stock with the end portions of the wire forming the two straight cantilever springs 56 comprising spring finger 26. The spring ends 58 of the springs 56 are severed from a continuous length of spring stock to provide smooth corners 60 for engagement within the recess at'contact arm ends 44 as indicated in FIG. 20. The smooth corners 60 and recesses prevent binding between the spring finger and arm during insertion of a lead into the socket 10.

Spring arm 24 comprises a flat U-shaped medial portion of the spring wire including a pair of straight cantilever springs 62 and a connecting U bend 64. The interconnecting spring portions 28 each include short torsion springs 66 extending outwardly from the cantilever springs 56 and 62 to bridging cantilever springs 68.

The socket body 16 may be rolled from portions of sheet metal stock on a carrier strip 70 as illustrated in FIG. 2l. The seam 40 at collar 30 is left open to permit insertion of the end of pin 35 prior to closing the collar about the pin and forming a reflow solder connection therebetween. A groove or recess 72 is formed in each body side wall 36 extending along the strap 20 slightly above the juncture between the contact arms and the strap. Spring 18 is fitted or wrapped around the socket body 16 with the bridging portions 68 of the spring positioned in the recesses 72 so that the spring arms 24 and 26 extend along the outside of the contact arms 22 with the free ends thereof 64 and 58 seated in the recesses at arm ends 44. Contacts 48 may be provided with a precious metal coating to reduce contact resistance.

The bridging portions 68 are spaced apart a distance slightly less than the spacing between recesses 72 so that when the springs are mounted on the bodies spring arms 62 are held apart slightly and the bridging portions 68 are biased against the recesses 72, thus holding the spring in proper position on the body. The connection between the ends of the spring fingers and the Contact arm also serve to hold the spring in proper position.

ln spring 18, as illustrated in FIG. 25, the free ends of the spring arms are normally positioned adjacent each other. When the spring is fitted on the socket body, the spring tension normally holds the contact portion 48 of arms 22 against each other. By prestressing the spring it is possible to preload the contacts and achieve a high contact pressure. Insertion of lead l2 through opening 17 and into the socket body forces apart contact arms 22 and stresses the spring 18.

lt is important to note that spreading of the contact arm stresses each portion of the spring 18. The springs 56 and 62 are bent outwardly and stressed as cantilever springs, the four torsion springs 66 are stressed by rotation and the bridging portions 68 are stressed as cantilever springs. With this construction the entirity of the spring is stressed with the result that a high spring force is applied to the contact arms. As mentioned previously, this force is multiplied because of the location of the contacts 48 with relation to the connection between the spring fingers and contact arms.

Because ofthe nature of spring 18, the pressure between the contact arms and the lead 12 is directly proportional to the deflection of the contact arms for leads of varying thickness. Thus it is possible to use the socket for forming reliable electrical connections with relatively thinleads as shown in FIGS. 2 and 5 and with leads having a greater thickness. This flexibility permits the use of the same socket for forming electrical connections with any of a variety of` leads thereby reducing inventory requirements while assuring that a high pressure electrical connection is formed with all leads. ln-

sertion of leads into the socket elastically deforms the springs 18 so that the contact pressure does not decrease with repeated insertions of the lead into the socket. This is important where the socket is used for forming connections with leads of integrated circuit elements or other elements where it is contemplated that the leads may be withdrawn from the elements and reinserted during the useful life of the socket.

The width of fingers 22 and their dished configuration assures that all leads inserted within the socket are forced between the fingers with the result that an electrical connection is formed. As illustrated in FIG. 9, the socket may be used to form an electrical connection with round leads 80. Even if' round leads are not inserted along the longitudinal axis of the socket and contact a side wall 36, the contact fingers 22 engage the lead to form the desired electrical connection.

As illustrated in FIGS. l, 3 and 4, the socket 20 may be positioned in a circuit board hole 32 with a printed circuit pad 74 surrounding the end of the hole adjacent the socket body to permit formation of a solder connection 76 between the socket and the pad. lf hole 32 is plated, the bottom of circuit board 34 may be wave soldered so that solder flows up through the passages 78 defined by the edges of collar 30 and the interior surfaces of the plated hole to provide solder for the connection 76.

FIG. 9 illustrates a modification of terminal l0 in which a pair of tabs 82 are lanced out of side walls 36 to permit positioning of the lower portion of the socket within oversize circuit board hole 84 extending through the thickness of board 86. The tabs 82 may be soldered directly to a printed circuit pad 88 surrounding the top of' hole 84. By mounting the sockets 10 on the circuit board in this manner, it is possible to locate the circuit components carried by the sockets closer to the circuit board thus resulting in a lower profile and in a saving of space. The saving of space is important in computers and other apparatus containing a large number of circuits when limited space is available or where components are required to be located close together to achieve high speed operation. FIGS. 10 and l2 illustrate a modification of the invention in which the collar 30 at the bottom of the socket body is crimped around a solder flow plug 90, in this case a cylindrical plug of Teflon. As indicated in FIG. l2, the walls of the collar 30 are deformed inwardly so that the collar tightly grips the plug. The collar and plug may be fitted within a plated circuit board hole 92 extending through the thickness of board 94 so that upon wave soldering molten solder wicks up through the four channels 96 defined by the walls of the collar and the plating at the sides of the hole to provide a solder connection between 98 with printed circuitry 100 on the top of the board. The plug 90 serves to prevent the molten solder from flowing into the interior of the socket.

FIGS. 11 and 13 illustrate a further embodiment of the invention in which socket body 16 is formed without a collar 30 on the lower end thereof, and the lower half of the socket body is fitted within solder impervious cup 102. The cup is generally square in cross section having side walls 104 closely fitted against the socket body side walls 36 and 38. The bottom of the cup forms a projection 106 which is useful in seating the socket and cup within a circuit board hole 108 formed through the thickness of board 110. Lip at the edge of the cup limits insertion into hole 108. The circuit board 110 may then be wave soldered to provide a solder connection 112 between the cup and printed circuitry 114 on the bottom of the board. A reflow solder connection or other suitable electrical connection is formed between the cup andl the body ofthe socket so that an electrical connection is formed between circuitry 114 and a lead positioned within the socket. This type of low profile mounting permits wave soldering of the socket to form the electrical connection while also assuring that the molten solder is prevented from entering the socket body.

FIG. 16 illustrates a modification of the socket shown in FIG. 2 in which locking barbs or lances 118 are formed in the corners 120 of collar 30. When the collar is tightly fitted into circuit board hole 122, formed through the thickness of board 124, the barbs 118 engage the interior of the hole and prevent movement of the socket 10 with respect to the circuit board prior to and during formation of the solder connection 126 between the socket and printed circuitry 128 on the top of the circuit board. The barbs may be formed prior to or subsequent to rolling of the sheet metal stock to form the socket body 16.

FIGS. 14 and 15 illustrate two embodiments of the invention in which the bridging portions of reinforcing spring 18 pivot on the socket body side walls 36 thereby permitting insertion of axially offset leads into the socket. Leads 12 are connected to the body of circuit element 14 at a point 130 located above the lead receiving opening 17 of the socket. As indicated schematically in FIG. 19, the axial alignment 132 of the leads may not coincide exactly with the axis 133 of the socket. Thus the leads may extend from point 130 within the socket to one side or the other side of the axis ofthe socket. It is important that the socket receive and form electrical connection with the offset leads without stressing the leads unduly and thus risking injury to circuit element 14. To this end, means are provided to permit the spring 18 to pivot slightly on axis 140 with regard to the socket body 16 thereby allowing the contact arms 22 to swing together to one side or the other side of the axis of the socket for reception of offset leads. Pivoting of the spring assures maintenance of an electrical contact with the lead despite vibration or shock loading of the circuit board.

ln the embodiment illustrated in FIGS. 14 and 18 the centers of the bridging portions 138 of spring 18 are bowed inwardly so that they are held against the recesses 72 at the center of socket body side walls 36 thus permitting slightly pivoting of the entire spring about axis 140 as indicated. Freedom to pivot permits the socket to receive and form a high pressure electrical connection with each side of leads offset somewhat from the axis of the socket without subjecting the lead to unbalanced forces which could injure the circuit element from which the lead extends.

FIGS. and 17 illustrate an alternative pivot connection to that illustrated in FIGS. 14 and 18 in which pivot projections 144 are provided within the recesses 72 at the middle of sides 36. Spring bridging portions 146 rest upon projections 144 to permit the desired pivotal movement of the spring upon insertion of axially offset leads.

FIGS. 24, 26, 27 and 28 relate to a further embodiment of the invention utilizing a reinforcing spring 148 which is stamp formed from flat spring metal stock.

The spring may be used with sockets identical to those previously described.

Spring 148 is stamp formed from sheet metal spring stock as illustrated in FIG. 27. Generally hourglass shaped hollow spring preform 152 may be formed from the flat spring stock by a stamping operation as an integral part of a continuous carrier strip 154. The preform 152 comprises a continuous strip of spring metal in the general shape of an hourglass having four tapered spring arms 156. The two spring arms on each edge of the spring preform are connected together by a sinuous portion 158 having a pair of curved contacts 160 facing the interior of the preform. The other ends of the spring arms 156 are connected by parallel bridging members 162. The flat stamped preform 152 is symmetrical to either side of axis 164. Preforms 152 are secured to strip 154 by severable connections 165.

Following stamping of the preform, the next step in the formation of the spring 148 illustrated in FIG. 26 is to bend the ends of the spring fingers 156 adjacent bridging members 162 to form offsetting steps 166 which lower the spring fingers below the bridging members. Following formation of steps 166, manufacture of spring 148 is completed by bending the preform nearly 180 about axis 164 so that the bridging members 162 are opposite each other and spaced outwardly of the spring by offsets 166. The manufacturing operations are carried out with the preform secured to a carrier strip, as illustrated in FIG. 22. vFollowing completion of the spring 148, connections 165 maybe severed to permit mounting of the spring on the body 168 of socket 150.

As indicated in FIG. 24, spring 148 is fitted on a socket body 168 by positioning the bridging members 162 in the recess 170 on strap 172 located adjacent the lead receiving end of the body. The bridging portions rest flat against the strap. The spring arms 156 extend along the outer surface of the socket body contact arms 174 with the rounded contacts 160 seated in the recesses defined by the curved ends of the contact arms to reduce binding. The remainder of the spring arms 156 are free of the contact arms.

Insertion of a lead 176 into socket 150 forces apart contact arms 174 and stresses the spring 148. Springv arms 156 act as cantilever springs. Because the arms decrease in width from the offsets 166 to the contacts 160 they are uniformly stressed when deflected resulting in maximum spring force. Offsets 166 are stressed as torsion springs and bridging members 162 are stressed as cantilever springs. Thus, as with spring member 18, each portion of the spring 148 is stressed to bias the lead contacts of socket into high pressure connection with the lead 176. The result is a highly efficient socket capable of receiving a variety of leads of different thicknesses and cross sections without stressing the spring beyond the elastic limits of the component spring parts. Contact pressure thus is retained despite repeated insertions and withdrawals of leads within the socket.

In both sockets 10 and 150, it is possible to vary the contact characteristics of the socket by varying the parameters of the spring used to urge the contact arms into engagement with the lead. Thus, in each case, the characteristic of the spring arms which engage the contact arms of the torsion springs and of the bridging cantilever springs, maybe adjusted to achieve the desired socket parameters. Adjustment of the spring characteristics is particularly easy in the case of spring 148 since the width of the various spring members is easily controlled in the stamping operation. For instance, for

a weaker spring, the tapered width of the spring arms 156 and of the remaining springs could be reduced. ln each case it is desirable to balance the characteristics of the three types of springs within each of the socket springs 18 and 148 so that the contemplated use of the socket does not stress any individual spring beyond its elastic limit.

The socket 150, as previously described sockets, may be provided with a wire wrap pin, solder plug, solder cap or other means for forming an electrical connection with a circuit element. Obviously the sockets described herein may be provided with a crimp barrel for forming a crimp connection between the socket and a wire. While the disclosed embodiments all show formation of an electrical connection with the socket adjacent the collar, it is not intended that the invention be limited to such a connection. Obviously a wire crimp barrelor other contact means could extend from the lead receiving opening or from other portions of the socket.

Accordingly, while l have illustrated and described preferred embodiments of my invention, it is understood that these are capable of modification, and l therefore do not-wish to be limited to the precise details set forth, but desire to avail myself of such changes and alterations'as fall within the purview of the following claims.

What l claim as my invention is:

l. A female contact having a longitudinal passage for reception of a male lead, the contact including a body formed of material having a high electrical conductivity and a spring formed of high yield strength material; said body comprising a band surrounding an end of the passage, a pair of opposed contact arms extending from the band along the passage with the free ends of the arms normally positioned in the passage, and means joining the band for forming an electrical connection with a circuit element; and said spring comprising mounting means for securing the spring to the band, and a pair of cantilever spring arms overlying and extending from the band longitudinally along the outside surfaces of said contact arms and joining said mounting means on the outer circumference of said band at the junctions of the contact arms and the band with the ends of said spring arms engaging the free ends of the contact arms.

2. A contact as in claim 1 wherein the spring is formed of a single length of spring metal and includes a band engaging member extending around the out-side of the band, and each of the spring arms comprises two portions of the spring metal, each portion extending from the band along the outside of the spring arm to a position adjacent the free end of the spring arm.

3. A contact as in claim 2 wherein the spring is formed of a length of spring wire of uniform cross section, one of the spring arms includes a U-shaped connection between the ends of the portions and the other spring arm includes the end portions of the spring wire.

4. A Contact as in claim 2 wherein part of the spring is fitted-within a groove formed in the band and extending generally between the junctionsof the fingers and the band.

5. A female type disconnect socket having a longitudinal passage for the reception of a male lead comprising an elongate hollow socket body formed of high electrical conductivity material and having an opening at one end for reception of the lead and means at the other end for forming an electrical connection with a circuit element, a pair of opposed contact arms formed in the medial portion of the socket body and extending into the body from one end thereof with the free ends thereof adjacent each other; and a reinforcing spring formed of high yield strength material including a portion wrapped around said one end of the body and spring arms extending from said portion along the outside of the contact arms to a position adjacent the free ends thereof for providing contact pressure between the contact arms and the lead when inserted into the socket.

6. A socket as in claim 5 wherein the portion of the spring is confined within a groove in the socket body.

7. A socket as in claim 5 wherein said spring arms comprise cantilever spring members and said spring portion includes at least a single torsion spring member.

8. A socket as in claim 5 wherein the medial portion of each of said contact arms includes reinforcing means for preventing buckling. l

9. A socket as in claim 8 wherein the free end of each contact arm is bent outwardly of the socket body to provide a recess for receiving the free end of the adjacent spring arm.

10. A socket as in claim 5 wherein said spring comprises a continuous length of spring metal with the free ends of the length located at the free ends of one of the spring arms, the other spring arm comprising a U- shaped portion of the length and the portion comprising two lengths of spring metal joining the spring arms.

11. A female contact having a longitudinal passage for reception of a male lead, the contact including a body formed of material having a high electrical conductivity and a spring formed of high yield strength material; said body comprising a band surrounding an end of the passage, a contact arm extending from the band along the passage with the free end of the arm normally positioned in the passage, and means joining the band for forming an electrical connection with a circuit element; and said spring comprising mounting means for securing the spring to the band, and a cantilever spring arm overlying and extending from the band longitudinally along the outside surface of the contact arm and joining said mounting means on the outer circumference of said band at the junction of the contact arm and the band with the end of said spring arm engaging the free end of the contact arm.

12. A contact socket comprising an elongate socket body open at oneend, means for forming an electrical connection to a conductor, a longitudinal cantilever contact arm formed from the body and extending into the interior of the body for engagement with a lead inserted therein, and a spring member on the outside of the body including a cantilever spring arm overlying and engaging the outside surface of the contact arm to bias the contact arm toward the interior of the body and a clasp member extending at least partially around the outside circumference of the body and resiliently engaging the body for securing the spring member to the body.

13. A contactas in claim l2 including a displacement resistant connection between the body and the clasp.

14. A contact socket comprising an elongate socket body open at one end, means for forming an electrical connection to a conductor, a pair of longitudinal contact arms formed from the body and extending into the interior of the body for engagement with a lead inserted therein, and a spring member on the outside of the body including a pair of springs engaging the outside surfaces of the contact arms to bias the contact arms toward the interior of the body and a resilient clasp connection extending at least partially around the outside circumference of the body to secure the spring member thereto.

15. A contact body as in claim 14 wherein said clasp connection includes at least one spring member associated with each of the springs for biasing the contact arms toward the interior of the body.

16. A contact socket as in claim l wherein said clasp connection includes a torsion spring member associated with each contact arm.

17. A female contact having a longitudinal passage for the reception of a ma-le lead therein, said contact comprising a body having a band portion disposed at each of opposite ends of such passage, a pair of side walls extending between said band portions and integral with each said band portion, said side walls defin ing opposite sides of said longitudinal passage, a pair of contact arms integral with one of the band portions and extending generally longitudinally from opposite sides thereof, said contact arms and said side walls cooperating to form a generally enclosed passage between said band portions, said contact arms being bent inwardly to approach each other adjacent the free ends thereof for engagement with said male lead, means extending from said body for connecting said female contact to an electrical conductor, and spring means secured on the outside of said body including two spring members for biasing said contact arms inwardly toward each other.

18. A female contact as in claim 17 wherein said spring means includes a mounting portion carried by said body adjacent said open end thereof and said spring members comprise cantilever springs extending along the outside surface of said contact arms for engagement therewith at a point adjacent the free ends thereof.

19. A female contact as in claim 18 wherein said spring means includes torsion springs cooperable with said cantilever springs for biasing said contact arms inwardly toward each other.

20. A female contact as in claim 17 wherein each of said contact arms includes anti-buckling means and a lead contact located between the junction of such contact arm with said one band and the contact point between the arm and the spring member.

21. A female socket comprising a body having a longitudinal passage for reception ofa lead, and a longitudinal contact member engagable with such lead; and a reinforcing spring on said body having a pair of opposed spring arms, each spring arm including a pair of closely spaced cantilever spring members, and a pair of laterally offset bridging portions joining the ends of spring members of different spring arms, said bridging portions being spaced` further apart than the spacing between the ends of the spring members of the spring arms and a connection between the other ends of at least one pair of spring members, the other ends of one spring arm engaging said longitudinal contact member.

22. A female socket as in claim 21 wherein each said bridging portion includes a pair of torsion springs and a cantilever spring.

23. A female socket as in claim 2l formed of a continuous length of uniform cross-section spring wire with the ends of the spring wire forming the other pair of spring members.

24. A female socket as in claim 2l wherein the crosssectional area of each of said cantilever spring members decreases along the length thereof from said bridging portions.

25. A female socket comprising an elongate hollow socket body at one end, a band at the open end, a pair of contact arms extending into the interior of the body from the band, a spring wrapped around the body adjacent said band and including spring arms extending along the exterior surfaces of the contact'arms for hold ing the contact arms into engagement with a lead inserted into the body, and a pivot connection between said spring and band to permit pivotal movement of the spring about an axis perpendicular to the longitudinal axis of the body.

26. A female disconnect socket comprising an elongate hollow socket body open at one end and having a pair of opposed contact arms formed therein with the free ends thereof extending away from the open end and into the interior of the body, and a spring including a pair of spring arms extending along the outside of said contact arms with the free ends of the spring arms en gaging the free ends of the contact arms, lead contact areas on the inside of said contact arms, each spring arm comprising a pair of cantilever spring members with the ends of at least one pair of spring members being joined, and bridging members surrounding the outside of the socket body and joining together cantilever spring members of each spring arm, each of said bridging members including torsion springs extending laterally from the joined cantilever spring members and a cantilever spring joining said torsion springs, said torsion springs and said cantilever springs extending around the circumference of said body whereby insertion of a lead into the socket forces the contact arms apart and stresses said cantilever spring members, said torsion springs and said cantilever springs.

2 1, A.fsmalerdisonnest Sask@ as .in Claim 26 wherein said contact areas are located between the free ends of the spring arms and the junction between the spring arms and the socket body.

28. A female disconnect socket as in claim 26 including a pivot connection between said body and each bridging member whereby the spring is free to pivot relative to an axis perpendicular to the longitudinal axis of the body.

29. A female disconnect socket as in claim 28 wherein said pivot connection comprises a reduced larea contact between the body and each cantilever spring.

r k ik r lUNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent'No. 3'781'770 Dated December 25; 1973 Inventor(s) Lloyd Mancinl It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column l, line 6, change "pring" to --vspring-n Column ll, line 13, change "body" to so`cket.

Column-l0, line 32, change "ends", second occurrence, to end.

lColumn' 12, line 17, after "body", insert -open.

signed and .walled this 50th day of July-1971+.

(SEAL) Attest:

McCOY M. GIBSON, JR. I C. MARSHALL DANN Attesting Officer Commissioner'A of Patents FORM PO105D (1D-69) A usCQMM-DC 503754259 .v n.5. Govznuuzuf "umso omc: 1 un o-sss-Jal 

1. A female contact having a longitudinal passage for reception of a male lead, the contact including a body formed of material having a high electrical conductivity and a spring formed of high yield strength material; said body comprising a band surrounding an end of the passage, a pair of opposed contact arms extending from the band along the passage with the free ends of the arms normally positioned in the passage, and means joining the band for forming an electrical connection with a circuit element; and said spring comprising mounting means for securing the spring to the band, and a pair of cantilever spring arms overlying and extending from the band longitudinally along the outside surfaces of said contact arms and joining said mounting means on the outer circumference of said band at the junctions of the contact arms and the band with the ends of said spring arms engaging the free ends of the contact arms.
 2. A contact as in claim 1 wherein the spring is formed of a single length of spring metal and includes a band engaging member extending around the out-side of the band, and each of the spring arms comprises two portions of the spring metal, each portion extending from the band along the outside of the spring arm to a position adjacent the free end of the spring arm.
 3. A contact as in claim 2 wherein the spring is formed of a length of spring wire of uniform cross section, one of the spring arms incluDes a U-shaped connection between the ends of the portions and the other spring arm includes the end portions of the spring wire.
 4. A contact as in claim 2 wherein part of the spring is fitted within a groove formed in the band and extending generally between the junctions of the fingers and the band.
 5. A female type disconnect socket having a longitudinal passage for the reception of a male lead comprising an elongate hollow socket body formed of high electrical conductivity material and having an opening at one end for reception of the lead and means at the other end for forming an electrical connection with a circuit element, a pair of opposed contact arms formed in the medial portion of the socket body and extending into the body from one end thereof with the free ends thereof adjacent each other; and a reinforcing spring formed of high yield strength material including a portion wrapped around said one end of the body and spring arms extending from said portion along the outside of the contact arms to a position adjacent the free ends thereof for providing contact pressure between the contact arms and the lead when inserted into the socket.
 6. A socket as in claim 5 wherein the portion of the spring is confined within a groove in the socket body.
 7. A socket as in claim 5 wherein said spring arms comprise cantilever spring members and said spring portion includes at least a single torsion spring member.
 8. A socket as in claim 5 wherein the medial portion of each of said contact arms includes reinforcing means for preventing buckling.
 9. A socket as in claim 8 wherein the free end of each contact arm is bent outwardly of the socket body to provide a recess for receiving the free end of the adjacent spring arm.
 10. A socket as in claim 5 wherein said spring comprises a continuous length of spring metal with the free ends of the length located at the free ends of one of the spring arms, the other spring arm comprising a U-shaped portion of the length and the portion comprising two lengths of spring metal joining the spring arms.
 11. A female contact having a longitudinal passage for reception of a male lead, the contact including a body formed of material having a high electrical conductivity and a spring formed of high yield strength material; said body comprising a band surrounding an end of the passage, a contact arm extending from the band along the passage with the free end of the arm normally positioned in the passage, and means joining the band for forming an electrical connection with a circuit element; and said spring comprising mounting means for securing the spring to the band, and a cantilever spring arm overlying and extending from the band longitudinally along the outside surface of the contact arm and joining said mounting means on the outer circumference of said band at the junction of the contact arm and the band with the end of said spring arm engaging the free end of the contact arm.
 12. A contact socket comprising an elongate socket body open at one end, means for forming an electrical connection to a conductor, a longitudinal cantilever contact arm formed from the body and extending into the interior of the body for engagement with a lead inserted therein, and a spring member on the outside of the body including a cantilever spring arm overlying and engaging the outside surface of the contact arm to bias the contact arm toward the interior of the body and a clasp member extending at least partially around the outside circumference of the body and resiliently engaging the body for securing the spring member to the body.
 13. A contact as in claim 12 including a displacement resistant connection between the body and the clasp.
 14. A contact socket comprising an elongate socket body open at one end, means for forming an electrical connection to a conductor, a pair of longitudinal contact arms formed from the body and extending into the interior of the body for engagement with a lead inserted therein, and a spring memBer on the outside of the body including a pair of springs engaging the outside surfaces of the contact arms to bias the contact arms toward the interior of the body and a resilient clasp connection extending at least partially around the outside circumference of the body to secure the spring member thereto.
 15. A contact body as in claim 14 wherein said clasp connection includes at least one spring member associated with each of the springs for biasing the contact arms toward the interior of the body.
 16. A contact socket as in claim 15 wherein said clasp connection includes a torsion spring member associated with each contact arm.
 17. A female contact having a longitudinal passage for the reception of a male lead therein, said contact comprising a body having a band portion disposed at each of opposite ends of such passage, a pair of side walls extending between said band portions and integral with each said band portion, said side walls defining opposite sides of said longitudinal passage, a pair of contact arms integral with one of the band portions and extending generally longitudinally from opposite sides thereof, said contact arms and said side walls cooperating to form a generally enclosed passage between said band portions, said contact arms being bent inwardly to approach each other adjacent the free ends thereof for engagement with said male lead, means extending from said body for connecting said female contact to an electrical conductor, and spring means secured on the outside of said body including two spring members for biasing said contact arms inwardly toward each other.
 18. A female contact as in claim 17 wherein said spring means includes a mounting portion carried by said body adjacent said open end thereof and said spring members comprise cantilever springs extending along the outside surface of said contact arms for engagement therewith at a point adjacent the free ends thereof.
 19. A female contact as in claim 18 wherein said spring means includes torsion springs cooperable with said cantilever springs for biasing said contact arms inwardly toward each other.
 20. A female contact as in claim 17 wherein each of said contact arms includes anti-buckling means and a lead contact located between the junction of such contact arm with said one band and the contact point between the arm and the spring member.
 21. A female socket comprising a body having a longitudinal passage for reception of a lead, and a longitudinal contact member engagable with such lead; and a reinforcing spring on said body having a pair of opposed spring arms, each spring arm including a pair of closely spaced cantilever spring members, and a pair of laterally offset bridging portions joining the ends of spring members of different spring arms, said bridging portions being spaced further apart than the spacing between the ends of the spring members of the spring arms and a connection between the other ends of at least one pair of spring members, the other ends of one spring arm engaging said longitudinal contact member.
 22. A female socket as in claim 21 wherein each said bridging portion includes a pair of torsion springs and a cantilever spring.
 23. A female socket as in claim 21 formed of a continuous length of uniform cross-section spring wire with the ends of the spring wire forming the other pair of spring members.
 24. A female socket as in claim 21 wherein the cross-sectional area of each of said cantilever spring members decreases along the length thereof from said bridging portions.
 25. A female socket comprising an elongate hollow socket body at one end, a band at the open end, a pair of contact arms extending into the interior of the body from the band, a spring wrapped around the body adjacent said band and including spring arms extending along the exterior surfaces of the contact arms for holding the contact arms into engagement with a lead inserted into the body, and a pivot connection between said spring and band to permit pivotal movement of the spring about an axis perpendicular to the longitudinal axis of the body.
 26. A female disconnect socket comprising an elongate hollow socket body open at one end and having a pair of opposed contact arms formed therein with the free ends thereof extending away from the open end and into the interior of the body, and a spring including a pair of spring arms extending along the outside of said contact arms with the free ends of the spring arms engaging the free ends of the contact arms, lead contact areas on the inside of said contact arms, each spring arm comprising a pair of cantilever spring members with the ends of at least one pair of spring members being joined, and bridging members surrounding the outside of the socket body and joining together cantilever spring members of each spring arm, each of said bridging members including torsion springs extending laterally from the joined cantilever spring members and a cantilever spring joining said torsion springs, said torsion springs and said cantilever springs extending around the circumference of said body whereby insertion of a lead into the socket forces the contact arms apart and stresses said cantilever spring members, said torsion springs and said cantilever springs.
 27. A female disconnect socket as in claim 26 wherein said contact areas are located between the free ends of the spring arms and the junction between the spring arms and the socket body.
 28. A female disconnect socket as in claim 26 including a pivot connection between said body and each bridging member whereby the spring is free to pivot relative to an axis perpendicular to the longitudinal axis of the body.
 29. A female disconnect socket as in claim 28 wherein said pivot connection comprises a reduced area contact between the body and each cantilever spring. 